Answer:
The answer is Shaping.
Step-by-step explanation:
A father is trying to get his young son to eat his peas. At first, the father praises his son whenever he moves his fork near the peas; after the child does this reliably, the father praises him only if he actually puts a pea on his fork; then praise is only given when the child puts a pea on his fork and moves the fork toward his mouth. Darren carries on this way until the child eats his peas. The father is using shaping.